Gene sequence data from the small-subunit ribosomal RNA coding region were used to explore evolutionary relationships among the colonial spumellarian radiolaria (Polycystinea). Representatives from the two spumellarian families known to form colonies were considered including the following taxa: Sphaerozoidae: Collozoum pelagicum; Collozoum serpentinum; Rhaphidozoum acuferum; Sphaerozoum puncta...

The Arabian carpet shark, Chiloscyllium arabicum is endemic to the Gulf and northern Sea. aim of this work study reproduction maturity species. A total 87 males 139 females, including 19 egg-bearing individuals collected from bottom set longline fisheries in Saudi waters between October 2017 February 2019, were examined. size at 50% was estimated as 62.3 62.5 cm length (TL) for respectively. Ch...

1. Electrical activity accompanying motor activity can be recorded from the excised pharynx of Enchiridium punctatum. Multiple stimuli elicit behaviour which consists of an initial aperture closure followed by extension and then peristalsis. If the stimulus parameters are increased the preparation bends from side to side instead of proceeding through the behavioural sequence. Bending appears to...

The photosymbiotic ascidian fauna at Changi Beach, Pulau Semakau, Sentosa and St. John's Island, Singapore were surveyed. A total of five species, Diplosoma simile, Lissoclinum bistratum, Lissoclinum punctatum, Lissoclinum timorense and Trididemnum cyclops, were recorded, with Lissoclinum timorense and Trididemnum cyclops being newly recorded in Singapore. However, no photosymbiotic species wer...

T H E initial report in this series (Finnegan, 1961) emphasized the role of the endoderm in the postgastrula differentiation of the hypomeric mesoderm in Ambystoma punctatum. The effect of the endoderm appeared to be modified when the mass of mesoderm involved was increased and, under the in vitro experimental conditions employed, the endoderm did not influence the splanchnic layer of the hypom...