184 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 15 



Bay, James Island, February 12, 1933; and one with another specimen 

 from station 350-35, South Seymour Island, December 13, 1934. All 

 specimens were found along rocky shores. 



Anatomical description. — The species has the form typical of the 

 genus, namely, long, slender, and straplike (fig. 1). It is characteristic 

 of the members of this genus that they tend to curl on preservation, 

 apparently because the central part contracts more than the lateral 

 regions. As preserved specimens of Latocestus are hard to straighten and 

 usually show some damage in the process, it is difficult to get a measure- 

 ment of length. When unfolded as well as possible, the specimens ap- 

 peared to be 40 mm long ; but no doubt they are much longer than this 

 when alive and fully extended. The color of the preserved specimens is an 

 opaque grayish brown. The body margin is encircled by a continuous 

 band of minute eyes; this band is broad with more numerous eyes an- 

 teriorly and gradually diminishes posteriorly. Because of the difficulty 

 of straightening the specimens, and since they all appeared to have suf- 

 fered some damage to the thinner, more delicate anterior end, the dis- 

 tribution of the cerebro-frontal eyes could not be exactly determined. It 

 is shown approximately in fig. 1. The cerebral eyes are numerous and 

 closely placed, in two bands beginning behind the brain and extending 

 forward above it. Then, as frontal eyes, they spread out in the usual 

 fanlike manner between the brain and the anterior end. The frontal 

 eyes show less spread and a smaller number than in some other species of 

 Latocestus. 



The digestive tract, in so far as it could be seen in the rather opaque 

 whole mounts, has the form typical of the genus. The oval ruffled 

 pharynx is far back, located just in front of the posterior end. The long 

 main intestine proceeds forward from it in the median line almost to the 

 brain (fig. 1). 



The copulatory apparatus, as is typical in this genus, is found in the 

 short space between the posterior end of the pharynx and the posterior 

 body margin (fig. 1). Its structure in median sagittal section is shown 

 in fig. 2. The sperm ducts proceed posteriorly to a point behind the male 

 apparatus, where they turn forward and, as a pair of slender tubes with- 

 out any augmentation of musculature, pass on either side of the prostatic 

 vesicle to a point ventral to its proximal part. Here they unite to a com- 

 mon ejaculatory duct that proceeds posteriorly as a sinuous tube which 

 lies ventral to the prostatic vesicle and joins the duct of the latter at the 

 base of the penis papilla. The prostatic vesicle is therefore free, a char- 

 acteristic of the genus. It is an oval body, whose proximal interior con- 

 sists of a web of glandular follicles, while distally there is a large lumen. 



