A. E. Yerrill — Marine Planarians of New England. 485 



be characteristic, which is doubtful. Internally, the structure is very 

 similar, but the first part of the female duct (vagina) in this species 

 is relatively shorter and smaller, and the spermatheca is somewhat 

 swollen or flask-shaped, while that of L. variabilis is rather cornu- 

 copia-shaped. • The male organs are very much alike. 



The amount of the variations in form, proportions, and position of 

 the genital organs that may be produced by the presei-ving and hard- 

 ening fluids is, however, very uncertain. These closely allied forms 

 should be more carefully compared as to these organs, when living, 

 or at least before immersion in hardening agents. 



Leptoplana angusta, sp. nov. 



Plate xl, figure 8 ; Plate xliv, figures 2, 2a, 3. 



Body veiy changeable, in extension rather narrow and elongated, 

 elliptical or oblong, the length exceeding half an inch and equal to 

 about thi-ee times the bi*eadth, very thin, with the margins flexible, 

 and usually more or less undulated and curled ; the front end is 

 usually rounded ; the posterior end is often notched or emarginate 

 in the middle. 



The cerebral and dorsal clusters of ocelli blend, and form two 

 nearly straight and parallel fusiform groups, often nearly linear in 

 the small specimens, pointed at both ends, and situated well forward. 

 In the larger specimens these groups have a distinctly wider portion 

 behind the middle, composed of a small cluster of larger ocelli be- 

 longing to the dorsal groups, which are partially detached from the 

 cerebral groups ; but in the smaller specimens the dorsal ocelli can 

 hardly be distinguished from the others, which mostly lie in two 

 rows in each group. 



The retracted pharynx is large, elongated, elliptical, with numer- 

 ous short, nearly equal lobes along the sides, of which about twelve 

 or thirteen pairs can usually be distinguished. The mouth is some- 

 what behind the center of the pharynx. The stomach has numerous 

 lateral branches and a great number of terminal twigs which anas- 

 tomose pretty fi*eely distally. 



The reproductive organs extend entirely around the pharynx and 

 stomach, thus forming an opaque or dark colored elliptical zone. 

 The vasa defereittia in the larger specimens are often conspicuous 

 organs along the sides of the stomach. The uterine sacs in some 

 specimens are large and swollen with masses of eggs, opposite and 

 behind the posterior part of the stomach. The copulatory organs 



