514 A. E. Verrill — Marine PlanaricDis of N^ir England. 



it, and before his excellent paper had been published, I had i-esumed 

 the study of the species and prepared descriptions of the genus 

 and species for this article. Having received Professor Mark's 

 paper, just as the last pages of my own were going to press, I have 

 been able to add several additional anatomical facts of importance, 

 which I had not personally observed. Professor Mark, in his paper, 

 moreover, describes in detail the nervous system, and also numerous 

 additional features not here referred to, or only briefly mentioned. 



My own conclusions, in regard to the essential structure and 

 affinities of the genus, were perfectly in accord with those of 

 Professor Mark. The few additional details that I have given in 

 the preceding description are due to the larger sei'ies that I have 

 had for study, or to their different modes of preservation. 



Professor Mark informs me that he has found the egg-capsules of 

 this species in abundance on dead shells and stones in the harbor of 

 Wood's Holl, Mass. They are circular, flat on the lower side, by 

 which they are attached, and a little convex on the upper side, with 

 thin margins. I have not met with them myself. In several in- 

 stances 1 have seen living young individuals in the interior of the 

 body of adults, but it is quite possible that they had been swallowed 

 as food Avith other small prey. The mode of depositing the egg- 

 capsules is unknown. There seems to be no special opening adapted 

 to that purpose. Possibly they escape from the mouth. The speci- 

 men figured on pi. xli, fig. 11a, appears to contain egg-capsules in 

 process of formation, but as the specimen was not preserved, this 

 cannot now be confirmed. 



Doubtful Species. 

 TyphloCOlaX aCUtUS Stimpson, Prod, p. 3, 1857. 



Typhlolepta acuta Girard, in Stimpson, Invert. Grand Manan, p. 27, 1853; Diesing, 

 Rev. Turbell., p. 523, 1861. 



" Body depressed, ovoid, elongated, posteriorly rounded; anterior 

 extremity terminating in an acute point; mouth underneath, and 

 situated at about the middle of the body. Length about a sixteenth 

 of an inch. Ground color pale, with reddish confluent blotches 

 above. Found in considerable numbers creeping over the surface 

 of (Jhirodoia Icevis.'''' 



Dr. Stimpson (Prodroraus, p. ;J) referred this genus and species to 

 the Digonopora, but its internal structure was not known to him. 

 It is more probable that it belongs to the Acoela or Rhabdocoela. I 

 have not observed it myself, although I have collected numerous 

 specimens of the holothurian, on which it is said to be parasitic, in 

 the original locality. 



