i66 coE 



Nerves and Sense Organs. — Brain is of large size, with remark- 

 ably large ventral commissure. Cerebral sense organs remarkably 

 voluminous, situated immediately in front of brain, and extending 

 somewhat beside and beneath the ventral ganglion. Canal to exterior 

 is of large size, and extends well forward toward tip of head, to open 

 below lateral margin in a shallow oblique furrow. 



Reproductive Organs. — Sexual products are mature in August. 

 The most anterior reproductive pouches in the males are situated well 

 forward in the esophageal region, or, in other words, well in front of 

 the opening of the esophagus into the intestine. The anterior sper- 

 maries lie beneath the lateral nerves, but in the intestinal region, where 

 several spermaries appear in each transverse section of body, they are 

 found in smaller numbers above the nerves. The ovaries occupy sim- 

 ilar positions in the female. The eggs when mature are very large in 

 proportion to size of body, being fully one-third its diameter. 



Habitat. — Common among bryozoa and tunicates ( done) on piles 

 of wharf in the harbor of San Diego, Calif. 



12. TETRASTEMMA QUADRILINEATUM sp. nov. 



pi. XIV, fig. 5; pi. XX, figs. 12, 13. 



Body short, broad and stout ; somewhat flattened, but with rounded 

 edges. Head usually narrower than body; provided with the usual 

 pair of lateral oblique grooves, which appear as slight constrictions 

 opposite the posterior pair of ocelli. Intestinal region broad and some- 

 what flattened. Intestinal caeca not much branched ; reaching nearly 

 to brain region. 



Color. — General color of body whitish, with four longitudinal 

 deep brown stripes. Two of these stripes lie near lateral margins of 

 body, while the other two are situated symmetrically on the dorsal sur- 

 face. The two dorsal stripes are much the wider, and are each about 

 equal in width to the white median stripe which lies between them. 

 They are narrower on the head, and terminate anteriorly a little in 

 front of the anterior pair of ocelli. Posteriorly they extend to the end 

 of the body where they likewise become much narrower. These 

 broad dorsal stripes are smooth in outline, but the lateral stripes, which 

 are very much narrower, usually present a much broken and ragged 

 appearance. In some individuals the lateral stripes are fully three- 

 fourths as wide as the dorsal, but ordinarily they are less than half as 

 wide. The two lateral stripes are strictly marginal, and ordinarily do 

 not show from dorsal surface unless the animal is somewhat com- 

 pressed. They each terminate anteriorly in the vicinity of the lateral 



