1898.] NATURAL SCIENCES OF PHILADELPHIA. 255 



cal retractor at the posterior margin somewhat to the right of the 

 median line, shortly bifurcate distally. 



Pallial region (PI. XV, fig. 75). Kidney large, rounded nearly 

 filling the lung cavity. Ventricle exposed. 



Distribution: San Diego Co., California. 



No adequate discussion of the affinities of Anadenulus can be en- 

 tered upon until well-preserved specimens are collected permit- 

 ting an examination of the genitalia. Present information indicates 

 its proximity to Prophysaon, with which Anadenulus agrees in the di- 

 gestive tract and musculature. But the voluminous kidney, exposing 

 only the ventricle, the conspicuously tripartite sole, and the appar- 

 ent absence of that peculiar structure of the tail which distinguishes 

 Prophysaon, are all important characters indicating the distinctness 

 of the two genera. 



Turning to Old World genera, we find Avion differing in its tail 

 gland, posteriorly prolonged buccal retractor and complexly twisted 

 intestine. Geomalacus shows the same with still other differences ; 

 and in Anadenus the foot margin is very much narrower, the sole 

 not divided by longitudinal grooves, and the intestine is long and 

 spirally twisted. 



A. Cockerelli (Hemphill). PI. IX, figs. 12, 13, 1-1; PL XI, fig. 35; PI. XIV, fig. 

 6S ; PI. XV, fig. 75. 



Anadenus Cockerelli Hemphill, Nautilus, IV, p. 2 (May, 1890), W. G. Bin- 

 ney, Fourth Supplement to Terr. Moll.,V, p. 178, PI. i, f. 1 ; PI, iii, f. 5 (den- 

 tition). 



Anadenulus Cockerelli Cockerell, Ann. Mag. N. H. (6), VI, p. 278, 279 (Oct., 

 1S90). 



Alcoholic specimens have the foot blackish, with a short, light 

 stripe behind the mantle above, the sides below mantle and the head 

 pale ; mantle small, short, black with two festooned longitudinal 

 yellowish stripes. 



Length 9-1 3? mm. 



Cuyamaca Mts., San Diego Co., California (Hemphill). 



IV. BRIEF DIRECTIONS FOR COLLECTING, PRESERVING AND 



EXAMINING SLUGS. 21 



In the Northern States the best time for collecting slugs is in 

 early spring. From February to July, most well grown specimens 



31 As many of our American conchologists have not collected or studied 

 slugs especially, we have thought it not superfluous to append the following 

 notes on collecting slugs, with rough directions for their examination. It 

 will readily be understood that if the slug to be examined is of very small 

 size, or it is necessary to obtain all the data from one or two specimens, more 

 or less radical modifications of these instructions must be made. 



