Linton.— Seasonal Distribution of Parasites 53 



distome, recorded under the name Distomum simplex, 

 has been found in the tomcod in every month of the 

 year. Another small trematode, Gasterostomum incres- 

 cens, is recorded from the Barracuda (Sphyrama bore- 

 ahs) in the months of April, September, October and 

 November. 



CESTODA. 



A tetrarhynch, Rhynchobothrium imparispine, has 

 been found adult in the spiral valve of the winter skate 

 (Raja ocellata) in the months of April, May, June, Aug- 

 ust September, October and November. The larval stage 



of T w St °, de i a f a WMe distrib «««n "mong the fishes 

 of the Woods Hole region, where it is found encysted, 

 usually on the viscera, and not confined to any season 

 of the year. Another cestode recorded under the name 

 Dibothru m rugosum, is of frequent occurrence in the 

 cod, where it is usually found with the heads impacted in 

 T»n, P J v T C& - U haS b6en collected in th « months of 

 dSt ^ my ' AUgUSt ' ° Ct ° ber ' N ° Vember and 



I have called attention in previous papers to the ex- 

 ceptional case of flesh parasites afforded by the Butter- 

 hsh (Poronotus triacanthus) . For many years, during 

 a IZ " DS °f JU ' y ^ Au * USt > J have ^een examining 

 sitef tL 01 " T nUmber ° f butterfish for fle <* P^a 

 whose Jjl T S ! IS u CeSt ° de ' 0tob °thrium crenacolle, 

 Tpiral ^ /I V^ f ° Und most fluently i„ the 

 spiral valve of the Hammerhead Shark, and less fre- 



S^'f * ^^ and the Sha «ed Shark In 

 akn f I" 6 July a " d Au8ust records I have a few 

 afco for the months of June and September. On account 

 of the arge number of butterfish that have been exam 

 med it is worth while to scrutinize the statistics carefX 

 n order to see if there is any indication of an increase 



VXV^r" nSh aS the — ad "ance* 

 farltrvi s ™Pe observation it was obvious in the 

 earlier years in which this flesh parasite was studied 



