426 



largest species of the Anellum group, known by its very faintly ex- 

 pressed ribs, plug intermediate between the mucronate and ungulate 

 forms, and mouth not thickened, but with a slight contraction and 

 expansion like that of a preserve jar. The reticulating striulse in 

 the interspaces are only seen in very fresh specimens. The shell is 

 then glossy, and to a slight extent transmits the light. The oper- 

 culum in well-preserved specimens is almost flat ; but the drying of 

 the animal sometimes draws it into a concave form. The ten outer 

 volutions are conspicuously marked by a spiral rib. The shell in its 

 young state is quite smooth, and by no means accords with Mr. 

 Clark's surmise, that iSkenea rota may be the nuclear portion. At 

 this period it is known at once from C. glabrum by the sharply an- 

 gular plug. Whether the Cornuoides major and minor of Brown are 

 the young of the same species, or one of C. trachea and the other of 

 C. glabrutn, cannot easily be ascertained, except from the compara- 

 tive size. 



15 b. Caecum (Ttrachea, var.) obsoletum. 



C. {Anellum) t. "C. tracheae " simili ; sed multo minore, gracili ; 

 postice annulis distantibus, antice sublcevi ; tota superjicie mi- 

 nutissime longitudinaliter corrugata ; septo subungulato, mar- 

 gins laterali concavo. 



Long. -095, lat. -015— -02. 



Hab. Salamis (Bea?i). 1 sp. Mus. 



This solitary shell may be a starved form of the common species ; 

 but as it may belong to an iEgean type not yet investigated, it is 

 kept provisionally separate. 



16. Cjecvm gurgulio, ?n. s. 



C. (Anellum) t. parva, solida ; annulis xxx.-xxxv. rotundatis, 

 sube.ipressis cincta ; interstitiis minimis : septo mucronato, 

 mucrone parvo, subdextrorsum sito, margine laterali recto : 

 operculo ? . . . . 



Long. -077, lat. -017— -02. 



Hab. W. Indies, sponge of commerce. Mus. Brit. &c. 



1=Odontidium rugulosum (pars), Phil. loc. cit. 



The West Indian specimens quoted by Philippi probably belong 

 to this form, which may possibly prove to be a dwarf variety of C. 

 trachea. Seven specimens were found, one only of which was per- 

 fectly fresh. This displays no sign of the longitudinal corrugation 

 characteristic of C. trachea : moreover the plug is decidedly mu- 

 cronate, though very short ; and the rings are both fewer and 

 larger than in the European species. 



1 7. Cjecum tumidum, n. s. 



C. (Anellum) t. tereti, sublcevi seu annulis obsoletis ornata ; 

 apertura haud contract a, annulo tumido cincta ; septo mamil- 



