619 



slightly smaller than the postseptal part. The efferent duct arises 

 from the ventral surface of the latter close to the septum. The lumen 

 is more or less contorted in both anteseptal and postseptal parts. 



Spennarics. — The spermaries are in the usual position in XI. In 

 most of the preparations the germ cells show various stages of mitotic 

 division. In sexually mature specimens a large mass of developing 

 sperm cells nearly fills the somite, often pushing the septa into con- 

 tact with septa IX/X and XII/XIII. 



Sperm Ducts.— Tht spermiducal funnel (PI. XCVIII, Fig. 8) is 

 nearly cylindrical, and the length is approximately one and one halt 

 times the diameter. It is situated in the posterior part of XI with the 

 base in close proximity to the ventral part of XI/XII, and the long 

 axis is directed obliquely dorsad. The anterior end has a well- 

 differentiated reflected collar, distinctly set off from the body of the 

 funnel by a constriction. The sperm duct is rather long, contorted, 

 and confined to XII. 



Penial Bulb.— The penial bulbs (PI. XCIX, Figs. 9, 10) are in 

 close relation to the penial pores* and each is in^'olved in a very mate- 

 rial modification of the body wall. At each penial pore there is a deep 

 invagination and an interruption of the nuiscle layers. The character 

 of the hypodermis is abruptly altered, but the cuticula, slightly re- 

 duced in thickness, is reflected into the invagination as a lining. The 

 body of the bulb is composed of two kinds of cells: (i) large, glandu- 

 lar cells which occupy all of the dorsal and peripheral parts of the 

 bulb and have large spherical nuclei; and (2) long, narrow, columnar 

 cells which are situated in the interior of the bulb and are arranged 

 radially around the penial lumen* for its entire length. Cells of the 

 second type contain small ovoid nuclei at their inner ends and stain 

 very lightly. They merge gradually into ordinary hypodermal cells 

 at the ventral side of the bulb, which, in turn, give place to the 

 clitellar cells present in the mid-ventral region. The bulb is covered 

 by a well-developed musculature which is a continuation of the 

 circular muscle layer of the body wall. 



The bulb is a typical lumbricillid bulb as defined by Eisen ('05, 

 p. 8). He claims that this organ has taxonomic importance and can 

 be used in the characterization of species, genera, and subfamilies. 

 The structure of the bulb agrees also with his diagnosis of the genus 



*We shall not undertake a discussion of the homologies of the penial bulb, 

 but for the purposes of this paper shall designate the ectal opening of its 

 lumen as the penial pore (PI. XCIX, Fig. 10, pen. po.) instead of the spermi- 

 ducal pore, and the lumen itself (Fig \0,pen, linn.) as the penial linnen. This 

 latter is the same as Eisen's "extension of the sperm duct" and "elongation 

 of the sperm duct" ('05, pp. 108 and 8). 



