ART. 7 GESTODE PAEASITES OF BIEDS LINTON 37 



testes, is in maturing proglottides profoundly lobed. The vitelline 

 gland is a small, compact, blimtlj^-lobed gland lying on the median 

 line dorsal to the posterior margin of the ovary, and ventral to the 

 posterior margin of the shell-gland. 



In whole mounts of strobiles with ripe proglottides the uterus is 

 seen in earlier proglottides to be diffusely lobed. In regions of the 

 strobile where the proglottides are closely crowded, and many times 

 as broad as long, these lobes are more or less globular or pyriform 

 (fig. 119). In longer proglottides, where the length may be as much 

 as half the breath, the lobes of the uterus are elongated and lie in a 

 direction parallel to the axis of the proglottis (fig. 118). The ova, 

 so far as they could be made out in whole mounts, are oval-elliptical ; 

 immature ova appeared to have a maximum diameter of 0.018. A 

 mature ovum measured 0.039 by 0.015 in the two principal diameters. 

 The outer laj'er of longitudinal muscles is represented by about 100 

 bundles containing but few, 3 to 5, fibers. The inner layer consiste 

 of 8 small bundles which are easily overlooked. No circular fibers 

 were seen. 



Dimensions of specimen mounted in balsam : Length 112 mm. ; 

 breadth of scolex 0.25, of sucker 0.136; length of hooks 0.108; 

 breadth of neck 0.14; length of segments, 1 mm. from scolex, 0.02, 

 breadth 0.15; length of posterior segments 0.51, breadth 2.38; maxi- 

 mum breadth 3.00, length 0.51. 



RECORD OF COLLECTION 



Marila americana: 



1914, February 28. — Two strobiles and fragments. Dimensions 

 of larger in formalin : Length 115 mm. ; breadth of scolex 0.36, 

 of neck 0.22; maximum diameter of strobile 3.25. 

 U. S. N. M., Helm. Coll. 7876. 



HYMENOLEPIS MACRACANTHOS (Linstow) 



Figure 105-113 



Scolex. — Broader than long, suckers relatively large, with thick 

 muscular walls; rostellum cylindrical, its sheath extending into the 

 neck; hooks eight in number, 0.09 mm. in length; diameter of scolex 

 in balsam 0.26 mm., of suckers 0.075. The hooks agree in detail 

 with figures of H. macracanthos., but are smaller, being about 0.09 

 mm. in length, instead of exceeding 0.10 mm. 



StrohUe. — Segments begin rather abruptly close to the scolex, in- 

 crease in length and breadth slowly, but remain much broader than 

 long throughout. The male genitalia are fully developed while the 

 female genitalia are still rudimentary; genital pores unilateral, at 



