48 SUMMARY OF CURRENT RESEARCHES RELATING TO 



New Mesozoon.* — V. Dogiel describes Haplozoon armatum g. et sp. n., 

 which represents a new group of Mesozoa. It was found abundantly 

 in the anterior part of the intestine of an Annelid, Travisia forhesi, 

 attached to the wall. The youngest stage consisted of a single spindle- 

 shaped cell, with an anterior attaching apparatus. From this unicellular 

 stage there developed by nuclear division a two-celled stage. Beneath 

 the hard stilet there was a tuft of contractile pseud opodium-like attaching 

 filaments issuing from a single opening in the cuticle of the anterior 

 cell. More cells are divided off from the anterior cell, and as each new 

 cell is formed the others divide. Thus an elongated single-layered 

 animal with a few oblique rows of cells is formed. The largest specimen 

 was 0'5 mm. in length, and consisted of 56 cells. The 2-6 cells at the 

 posterior end become full of refractive bodies, and each divides into four. 

 These are the germ-cells, and they are liberated in pairs into the lumen 

 of the Annelid's gut. 



Echinoderma. 



New Californian Starfishes.f — W. K. Fisher describes from 

 Monterey Bay, California, Astropecteii calif ornicus sp. n., a long-rayed 

 form, with numerous actinal adambulacral spines. The infero-marginal 

 plates are narrow, with a transverse aboral series of about three spines on 

 .the edge of the ray, and with auxiliary spinules. Ahxa/idraster m flatus 

 sp. n. is also recorded from the same area. It has short and thick rays, and 

 strongly grooved adambulacral spines. The furrow spines are prominent, 

 and not conspicuously smaller than those of the actinal surface. 



Commensals of Echinoderms.J — Ch. Perez notes that the burrows 

 of Synapta often contain a Polycha^t {0})hiodromus flexuosus, one of 

 the Hesioniffi) and an Amphipod. The Polychaet has been hitherto 

 known only as a commensal of Astropecten, and the Amphipod as a 

 commensal of the burrowing Spatangid Echinocardium cordatum. Thus 

 the usual constancy of commensal association is not without exceptions. 

 Hitherto, however, Acholoe astericoJa has only been found on Astropecten. 



Species of Pseudocucumis and Phyllophorus.§ — Hjalmar Ostergren 

 seeks to get at the facts of the case in regard to Pseudocucumis mixta 

 Ostergren, PhyUophorus pellucidus Fleming, and Ph. communis v. Diiben 

 and Koren, which seem to have a perplexing synonymy. 



Coelentera. 



Alcyonarians from Zanzibar. ||— J. Arthur Thomson and W. D. 

 Henderson report on a collection of littoral Alcyonarians made by 

 Mr. Cyril Crossland at Zanzibar. The collection includes over 60 

 species, of which 25 are new. The most interesting new forms in the 

 collection are the following : — Clavularia pregnans (viviparous), Siphono- 

 gorgia intermedia (an annectent type), Codogorgia reptatis (with encrusting 



* Zool. Anzeig., xxx. (1906) pp. 895-9 (9 figs.). 



t Tom. cit., pp. 299-302. 



i Proc. Verb. Soc. Sci. Bordeaux, 1904-5, pp. 57-8. 



§ Arkiv. f. Zool., iii. No. 16 (1906) pp. 1-23 (3 figs.). 



II Proc. Zool. Soc. London, 1906, pp. 393-443 (6 pis. and 1 fig.). 



