370 APPENDIX. 



ventrali subcostato ; dentibus anticis ad numerum un- 

 decim, posticis novemdecim. 



This very interesting species is the fourth of this 

 peculiar divaricately ribbed group which has been dis- 

 covered in a recent state. The three others are Nucula 

 divaricata and N. castrensis of Hinds, and N. mirabilis 

 of Adams and Eeeve. This species approaches very 

 nearly to the fossil species from the Crag, N. cobboldice, 

 but differs from it in being less transversely ovate, in 

 having the beaks more prominent, the posterior row of 

 teeth in the hinge fewer in number (in N. cobboldice 

 they are 22), and in the costations being stronger in 

 proportion to the size of the shell, and much fewer in 

 number. It was with some hesitation that I decided 

 upon describing it as a new species ; but these marks, 

 the size, and the habitat all induce me to consider it as 

 distinct. I have named it after Dr. Lyall, of H.M.S. 

 ' Plumper,' who has sent us only one specimen. Long, 

 rather more than ^ inch ; lat. rather more than ^ inch. 



- Hob. Esquimalt Harbour, Vancouver Island ; 

 dredged by Dr. Lyall, H.M.S. ' Plumper,' in from 

 8 to 10 fathoms. (Brit Mus.) 



PECTENLTLE. 



Pecten hericius. (Gould.) Esquimalt Harbour, 8 to 10 fathoms water. 

 Hinnites giganteus. (Gray.) Kocks between tide marks. 



OSTKID.E. 



Ostrea edulis. (Lamk.) Abundant along the island and mainland 



coasts. 

 Placunanomia cipio. (Gray.) Eocks between tide marks. 



