360 SUMMARY OF CURRENT RESEARCHES RELATING TO 



remarkable diversity of structure in the eves of the deep-water Mysida-. 

 Materia] for interesting speculation may be found in the possible func- 

 tions of the processes of the eyes in the genera Dactylerythrops and 

 Peramblyops, or the carious equatorial membranous ridge of the eye in 

 Dactylamilyops lhawnatops. 



Annulata. 



Pelagic Polychsets of Irish Seas.* — R. Southern reports on live 

 Alciopinae, four Toniopteridae, and four Typhloscolecidae found as part 

 of the pelagic fauna off the coasts of Ireland — in the warm and com- 

 paratively highly saline waters of the European branch of the Gulf 

 Stream. They rarely cross the 200-fathom line. With the exception 

 of two species of Tomopteris, the recorded species are all new to British 

 marine area. 



Notes on Polychsets.j — W. C. Mcintosh discusses Syllides verrilli 



Moore which presents interesting features of relationship with Stauro- 

 cephalidse as well as wdth Syllids ; Nevaya ivhiteavesi g. et sp. n., from 

 the Gulf of St. Lawrence, a form with certain relationships to Sclerockeilus 

 Grube ; and a number of Cirratulids, e.g. species of Cltaetozone, from 

 Canada, Norway, and Britain. 



Polychsst from the Delta of the Volga. $ — A. Dershawin reports 

 the interesting occurrence of a species of Hypatina (probably invalida) 

 in the Delta of the Volga. It has hitherto been known only from the 

 Caspian Sea, where it has an extraordinarily varied distribution, from 

 5*5-264: m. in depth, hi diverse conditions of salinity, pressure, and 

 temperature. 



Development of Trochophore of Hydroides.§ — Creswell Shearer 

 describes the segmentation and gastrulation, the origin of the ectomeso- 

 blast and coelomesoblast, and the early trochophoral stages in Hydroides 

 uncinatus (Eupomatus). There is a round blastula with a much re- 

 duced blastocoel. Invagination produces at first an almost spherical 

 gastrula, which soon begins to assume the conical shape of the early 

 trochophore. The blastopore closes from behind forwards, the anterior 

 portion remaining as the mouth. The anus breaks through at the point 

 where the posterior end of the blastopore closes. 



At a time when gastrulation is about half completed, some cells appear 

 on either side of the endoderm ; they probably represent ectomesoblast ; 

 they form the head-kidneys, which open into the proctodaeum. At the 

 same time two conspicuous cells are usually distinguishable in the 

 ventral lip of the blastopore — the coelomesoblast. At a considerably 

 later stage they give rise to the mesoderm bands. 



Parasitic Castration of Earthworms. ||— Igerna B. J. Sollas found 

 a marked bacterial infection in a number of full-sized earthworms 



* Sci. Invest. Fisheries Ireland, iii. (1910, published 1911) pp. 1-37 (3 pis.). 



t Ann. Nat. Hist., vii. (1911) pp. 145-73 (3 pis.). 



J Zool. Anzeig., xxxvi. (1910) pp. 408-10. 



§ Quart. Journ. Micr. Sci., lvi. (1911) pp. 543-90 (3 pis. and 29 figs.). 



1 Ann. Nat. Hist., vii. (1911) pp. 335-7. 



+ 



