326 bulletin: museum of comparative zoology. 



gas. Later special attention was given this little Ophionereis, and I 

 am now satisfied that it is a young 0. olivacea, a species hitherto known 

 only from a single specimen, taken by the Fish-Hawk in February, 

 1899, in 6 fms. off the eastern end of Porto Rico. That specimen was 

 6 mm. across the disk and had arms about 33 mm. long. The speci- 

 men taken at Key West is 3.5 mm. in disk-diameter and the arms are 

 about 21 mm. long. In only one particular is there any essential 

 difference between the two. The small specimen has no yellow spots 

 on the disk; in life it was bright olive-green and white, but in the 

 preserved specimen, the green is now a deep gray. The characteristic, 

 long, club-shaped middle arm-spine is noticeable on four or five of the 

 basal arm-segments. The coarse scaling of the disk and the shape of 

 the arm-plates are alike in the two specimens. The differences in 

 coloration may then be construed as age-differences, as the Key West 

 specimen is evidently immature, and the identity of the two specimens 

 may be accepted. 



Ophionereis squamulosa. 

 Koehler, 1914. BuU. 84 U. S. N. M., p. 44. 



It may be of interest to record that this pretty little species is very 

 common in coralline Algae both at Buccoo Bay, Tobago and in the 

 Tortugas region. It has hitherto been known only from St. Thomas 

 (1 specimen) and from the vicinity of Parahiba Brazil (2 specimens). 

 The previously known specimens were only 2-3 mm. across the disk 

 but the adults from Tortugas are 5-6 mm. across the disk and have 

 arms, 40 mm. long. As a rule the color is very constant but one 

 Tortugas specimen (M. C. Z. 4,226) was, and still is, conspicuous in 

 having the ground-color light brown instead of the usual reddish 

 white. Specimens in alcohol are more as Koehler says "brun- 

 grisatre. " 



- OPHIOCOMIDAE. 

 Ophiopsila. 



This is a very sharply defined genus, easily recognized by the re- 

 markable tentacle-scales. Only four species were known to Lyman, 

 who placed the group between Ophiophragmus and Ophionereis, 

 but since 1898 six additional species have been described and the 



