l6o CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



pine in the Sierra Nevada mountains; Redding, Calif., 

 collected by Mr. Richard C. McGregor; San Francisco, 

 Calif., collected from flower pots by Mr. Charles Fuchs; 

 Orizaba, Mexico, collected by Mr. Albert Koebele. 



The species resembles M. -parvus in the arrangement of 

 the setce, but differs externally, somite I being broader. In 

 M. parvus somite I is much narrower on the ventral side 

 than on the dorsal, and the whole somite is much narrower 

 than somite 11. In M. Troyeri somite I is wider than somite 

 II, and is not narrower on the ventral side. M. Troyeri 

 possesses no ventral papillae on any of the somites. 



Microscolex Horsti, sp. nov. 



Plate XIV, Fig. 185. 



Definition. — Length 20 mm., width i>^ mm. Somites 45. Setae, begin- 

 ning with XXI, deltoid in arrangement both posterior and anterior to the 

 male pore. Small ventral paired tubercles in XI; two large ventral tubercles 

 in XIV adjoining and dorsal to the ovipores, which are in line with setae a. 

 The male pores are so close together that they appear to be situated on the 

 same papilla, between setae a, in XVII. Somite I is narrower than II, and 

 its dorsal side is half as wide as the ventral. Somites I-VI are a third nar- 

 rower than those following. Clitellum perfect in XIII-XVII. Penial setae 

 unequal, the longer curved, the shorter straight; both with the apex knob-like 

 and smooth.. Testes in X and XI. Sperm-sacs small, racemose, in XI and 

 XII. Sperm-ducts open into the muscular prostate. Prostate thick and 

 bent, confined to one somite. Spermathecae, one pair in IX, each with one 

 diverticle. A small rudimentary gizzard in V. 



Habitat. — One specimen found among roots of plants in 

 a flower pot brought from Honolulu, Hawaii. Taken in 

 April, 1898, by Mr. Alexander Craw, State Horticultural 

 Quarantine Officer of California. 



This species is well characterized. The close proximity 

 of the male pores, the single diverticle of the spermathecae, 

 the rudimentary gizzard, and the knob-like apex of the 

 penial setae serve to place it in the group formed by Micro- 

 scolex algeriensis and Microscolex modestus. 



Unfortunately the specimen is badly twisted and all 

 the points could not be determined, but enough was shown 

 to entirely separate it from the two nearest allied species. 



