TETHYS DACTYLOMELA (rANG) 



15 



External Characters. 



Six specimens of this widely distributed Antillean species 

 were found in the collection, five of them taken from the same 

 locality, "Coral reef, Maceio, Alagoas, July 30, 1899," and the 

 sixth from "Pernambuco stone reef, July 7, 1899," and collected 

 in both cases by A. W. Greeley. No further notes accompanied 

 the specimens, but, according to a verbal communication from 

 Mr. Greeley, the preserved material was of nearly the same col- 

 oration as in life, the ground color being slightly deeper, a yel- 

 lowish brown. The characteristic ink ejected on being disturbed 

 was of a deep purple color. Of the six specimens taken, one was 

 quite large, being over twice the length of any of the others, 

 which were of nearly the same dimensions throughout. All were 

 in a good state of preservation, but all more or less contracted, 

 especially in the region of the mouth and head. The following 

 table gives a comparison of the principal dimensions. 



In individual No. 3 the anterior end of the left parapodium 

 was 10 mm. behind that of the right side. In individuals Nos. 4 

 and 6 the contraction of the head region was so great as to 

 invalidate the measurements omitted in the table for all purposes 

 of comparison. 



Color. The general plan of coloration is the same as that 

 given in the revised description of this species in Tryon's Manual 

 of Conchology, Vol. XVI, p. 75, and quoted above. The black 

 rings form a very striking color characteristic, their centers being 

 free from pigment. They reach a diameter in the largest speci- 



