60 



LEODICID^ OF THE WEST INDIAN REGION. 



Marphysa acicularum Webster, var. brevibranchiata, new variety. 



(Plate 5, figures 5 to 8; text-figures 194 to 200.) 



At Flatts Inlet, Ely's Harbor, and Fairyland Creek, Bermuda, I found associated 

 with Marphysa acicularum a second form which, while agreeing with acicularum in 

 general, differs from it in the form of the jaw and gills. In some animals these might 

 be merely sex differences, but, so far as I know, sex differences do not occur in this genus. 

 Since the animals were not breeding at the time of my visit to Bermuda, I was unable 

 to determine this point, but believe that the differences are of a varietal character. 



The general appearance of the body (plate 5, figure 5) is very like that of M. acicula- 

 rum, but the prostomium is more evidently bilobed and there is a greenish tint on the 

 anterior region which does not appear on acictdarum. The tentacles are relatively longer 

 and the gills are much shorter and thicker. The general form of the body is very 

 similar in the two. 



Text-figures 194 to 200. 

 Marphysa acicularum Webster, 

 var. brevibranchiata Treadwell. 



194. One-hundredth parapodium xl4. 



195. Maxilla xl4. 



196. Mandible xl4. 



197. Compound seta x394. 



198. Simple seta x394. 



199. First parapodium x30. 



200. Tenth parapodium x24. 



The first parapodium has rather more slender cirri than in M. acicularum (text-figure 

 199). The tenth parapodium shows in the variety a longer and more slender ventral 

 cirrus than occurs in the species (text-figure 200), and the middle parapodia of the 

 species have a much more slender dorsal cirrus than has the variety. The anal cirri 

 are not noticeably different in the two. (Compare figure 4 with 8 on plate 5.) 



The gills begin in the region of somite 28, as in acicularum, but are always shorter 

 and with more branches than in the species. While I have never found more than 



