276 POLYZOA INFUNDIBULATA. 



The entire polypidom rarely exceeds half an inch in length, but 

 when perfect the branches are bent and intertwined so as to form a 

 little glomerous mass. 



" Incipit semper duplici lacinia, veluti furca, obliqua a rupe aliave 

 cui insidet basi prodeunte. Laciniee nunquam 2 lineis paris. lon- 

 giores observantur." Pallas. 



Milne-Edwards is of opinion that the T. serpens of 0. Fabricius 

 is not synonymous with the Linnsean species, but with the T. fim- 

 briata of Lamarck, in which opinion a re-perusal of the description, 

 in the Fauna Groenlandica, does not induce me to coincide. 



Our species is without any doubt the same as the Idmonea trans- 

 versa of Milne-Edwards, but it cannot, in our opinion, be separated 

 generically from T. phalangea and flabellaris. Indeed monstrous 

 specimens are sometimes met with which can with certainty be re- 

 ferred to neither of these species, except by reference to specimens 

 of a more normal character on the same site. 



I have seen small specimens on crabs and shells which correspond 

 exactly with the figure of Lamouroux's Obelia tubulifera, which I 

 consider to be Tub. serpens in an early state of existence, evolving 

 itself on the flat and even surface of a bivalve shell. 



9. T. HYALINA, " encrusting, semi-transparent, membrane-cal- 

 careous ; cells distant from each oilier, tubular, erect, arranged 

 in one or two circular rows round a plain centre ; apertures 

 unarmed and frosted.'''' R. Q. Couch. 



Tubulipora hyalina, Couch Zooph. Cornw. 47 : Corn. Faun. iii. 108. 



Hob. "On Fucus palmatus, rare. Polperro," R. Q. Couch. 



"Encrusting in small semi-transparent patches of about the 

 diameter of a pea. The cells are distant, erect, arranged in one or 

 two rows round a plain centre ; occasionally there are a few cells 

 irregularly arranged in a circumscribed patch in the centre, but 

 separated from the external rings by a plain surface. The apertures 

 are even, unarmed, with frosted rims." R. Q. Couch. 



2. DIASTOPORA,* Lamouroux. 



CHARACTER. Polypidom calcareous, encrusting, undefined; 

 the cells alternating, tubular, horizontal, immersed, with a 

 raised circular aperture. 



* As denned by us, the genus corresponds with the " Les Diastopores simples" of 

 Milne- Edwards. Mem. p. 39. The name appears to signify "having pores at 

 intervals," from Siaffrrf/jta an interval, and iropoQ a passage. 



