496 A. E. Verrill — Marine Planarians of Neio England. 



consists of twelve or more ocelli, of which one, near the middle in 

 each group, is larger than the rest. 



Color pale, translucent, yellowish or pinkish white, irregularly 

 specked and mottled, or veined, with purplish or brown, and usuallj^ 

 with a number of darker and more distinct, small, brown spots scat- 

 tered over the central area, and especially along the middle of the 

 back, while around the margin the color markings form distinct 

 radial spots. 



Length 10 to 12'""^ ; breadth 6 to 8™'°. 



Wood's Holl, on piles, July 14, 1881; in mud, Aug. 2, 1882; Nau- 

 shon I., near Wood's Holl, Mass., at low-water mark, among algae, 

 Aug. 20, 1887. 



This species has been met with but few times, and in each case 

 only a single specimen has been obtained. It must be considered 

 very rare on our coast. None of the specimens are sufficiently well 

 preserved to allow any anatomical study. 



Family, PROSTHiosTOMiDyE Lang, p. 594. 

 Prosthiostomum Quarrefages, op. cit., p. 133, 1845; Lang, op. cit., p. .594. 



Body elongated, smooth. No tentacles. Ocelli in cerebral groups 

 and around the front margin. Mouth anterior, below the brain. 

 Pharynx long, tubular, directed forward. Stomach elongated, with 

 numerous lateral branches, not anastomosed. 



Male genital organs behind the pharyngeal sac ; two accessory 

 seminal vesicles ; penis uncinate, directed backward. 



This is the only genus of the family. 



Prosthiostomum gracile Girard. 



ProHlhiostomnni yracile Girard. Proc. Boston Soc. Nat. Hist., vol. iii. p. 251. 1850. 

 Elanmodes f r/rociVis Stimpson, Prodromus, p. [3] 21, 1857. 



Woodcut, Fig. 1. 



The original description of this species is so meager that no one 

 has hitherto been able to identify it, so far as I know. 



It reads as follows : " It differs from other species of the same 

 genus by its very slender body and the arrangement of the eye- 

 specks, which are disposed in four groups ; of which the first and 

 second are in a single pair, the third triple, and the fourth double. 

 From Boston Harbor." 



The generic position has been doubtful. Dr. Stimj)Son, who states 

 that he had Girard's original drawings of planarians for examination, 

 refers it doubtfully to Elasmodes [= Leptoplana in part). 



