MEL\'ILL : OBITUARY NOTICE— A. J. JUKES-BROWNE. 283 



He had the misfortune to lose both his wife and son in his lifetime, 

 but is survived by his only daughter. 



It is, I think, worth while transcribing in extenso three letters almost 

 taken at random from his correspondence, written at the time when 

 he was most closely studying the intricacies of the family Veneridce, 

 both to shew his clear, lucid, and attractive style of writing, and the 

 thoroughness with which he encountered and mastered the knotty 

 difficulties and details of any subject he undertook to study. 



• Westleigh, Torquay, 



January 8, 1913. 

 Dear Mr. Melvill : 



I have recently been studying the Callista-Pitaria group of shells, 

 recent and fossil, with the hope of discriminating more satisfactorily between 

 the proposed genera. 



You have shown such kindly interest in my previous studies that I hope 

 I may enlist your interest in this one also. I think I can divide the group 

 into three genera by means of two chief criteria, which are associated with 

 minor points of distinction. 



These two points are the position of the left posterior cardinal, which I 

 will write of as L.p.c, and the channel occurring in front of the right anterior 

 cardinal in Pitaria, abbreviated as R.a.c. 



I. — ^If you will take a Callista chiotie you will see that the L.p.c. is a 

 short tooth, highest in the middle and confluent with the nymph, while there 

 is no channel leading to the anterior lateral pit in front of the R.a.c. 



2. — If you take Cytherea dione you will see that it has a long L.p.c, 

 confluent along its whole length with the nymph, and that there is a channel 

 in front of R.a.c. 



3. — If you take any Pitaria except P. tinnens, you will see that the 

 L.p.c. is entirely distinct from the nymph and extends to the inner margin of 

 the hinge-plate; while the plate of the R. valve is channeled, as in C. dione. 



Now Group I includes almost all the shells which have generally been 

 called Callista. The second is the Dione group as restricted by Romer, 

 together with the Ainiantis of Carpenter, which name it must bear, since 

 Dione was preoccupied by Hubner. 



The third group comprises most of the Pitaria shells, but unfortunately 

 P. tutnens (the type) is an exception, both in regard to the L.p.c. and the 

 depth of the pallial sinus, a correlative but subsidiary point. 



My collection of Pitaria is by no means complete, and there are many 

 species which I cannot get from Sowerby ; so I should be greatly obliged if 

 you would assist me by looking through your shells to see if you can easily 

 arrange them by my criteria, and whether there are any other species of 

 Pitaria (projier) which agree with P. ttunens, and differ from such species 

 as P. lata and var. obliquata, P. citrina, P. sjcbpellitcida, P. varians, etc. 



All the typical Pitaria seem to be either smooth or striated with fine 

 concentric lines. Those which are concentrically ribbed like P. tnanillcs, 

 P. injlata, and the little P. winuta, which you sent me from the Gulf of 

 Oman, have the L.p.c, which is characteristic oi Auiiantis [ — Dione). 



