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



Habitat. — Mexico and Central America. 



This worm was found to be very common in the 

 coast territory from the Cape Region in Baja California 

 through Mexico, Guatemala, and Salvador in Central 

 America. Specimens are represented from the following 

 localities in Baja California: Todos Santos, Miraflores, 

 San Jose del Cabo and all parts of the Cape Region. 

 (Eisen 21.) Todos Santos is the most northern point 

 where the species was found, and it is doubtful if it 

 extends further north. It has not been found in Cali- 

 fornia, U. S. A. In Mexico I have collected specimens in 

 abundance at Mazatlan, San Bias, and Tepic. As the lat- 

 ter place is over 4,000 feet above the sea, it will be seen 

 that the species possesses a great vertical range. I do not 

 think, however, that it occurs in localities subject to frosts. 

 In Guatemala, Salvador and Honduras, the species extends 

 from the Atlantic to the Pacific. The Cape Region speci- 

 mens are all from the lowlands. They are larger than 

 those from the mainland of Mexico and from Central 

 America, but I have found no other distinguishing feature. 



The anatomical and histological description given below 

 is based on specimens from Tepic, taken in the vicinity of 

 the city. The Central American specimens were not suffi- 

 ciently well preserved to warrant sectioning, and the Cape 

 Region specimens appeared to me to be so similar, except 

 in size, that no effort was made to study their finer anatomy. 



Characteristics. — The following points in the structure of 

 Pontoscolex corethruriis subsp. 'inexicanus are either espe- 

 cially characteristic of this form or they have not before 

 been mentioned as belonging to Pontoscolex corethrurus by 

 those who have previously studied the species. 



1. The septum III/IV is very wide and greatly thickened. 



2. Tubercula pubertatis are present in somites 

 XIX-XXII. The glandular cells characteristic of these 

 organs penetrate into the muscular layers of the body-wall. 



3. The spermathecae open into the posterior parts of 

 somites VI, VII, VIII, but the main pouches are in somites 

 VII, VIII, IX. The spermathecal pores are thus preseptal. 



