146 CALIFORNIA ACADEMY OF SCIENCES. 



bed of the river south of town at a water-hole in the otherwise dry creek bottom 

 sand. It occurred here with Deltania and Limnodrihis. The sand was merely moist 

 on account of overlying rubbish and sacks. The species is undoubtedly a native one 

 and the only Acanthodrilid found on the coast so far north in the open ground, and 

 and on this account even of geographical interest. The intestine of the worm was 

 o-orged with the coarse white sand of the river bed. The anterior part of the worm 

 was cut lengthwise, one-half dissected and the other half sectioned crosswise. The 

 want of specimens made a full investigation impossible, though I believe none of the 

 important points remains in doubt. I have no reason to believe the species is scarce, 

 though probably it is sharing the fate with all native worms, that of being displaced by 

 European importations. The species is dedicated to Professor W. S. Keyes, my com- 

 panion in many travels in tropical Mexico. 



Affinities. It is interesting to note that Aleodrilus shows considerable affinity 

 to the only other North American genus of this family, viz.: Diplocardia. It re- 

 sembled this genus by having two gizzards, no calciferous glands, meganephridia, no 

 sacs with penial set*. It resembles Benluimia in having two gizzards, etc., but it 

 differs from these two, as well as from all other Acanthodrilidtie, by the far backward 

 position of the prostate and spermiducal pores, these being in xx, xxi and xxii re- 

 spectively, while all other genera of this family have these respective pores in xvii, 

 xviii and xix. The genital male pores are thus in Aleodrilus pushed three somites 

 further back. Considering these and some minor characters I believe I am justified 

 in placing this worm in a new genus. 



Aleodrilus Keyesi n. sp. 



Definition. Length 7 cm., by 5 mm. wide; number of somites <S'0. I'ust dor- 

 sal pore viii-ir. Clitellum complete in (interior, incomplete in the posterior somites, 

 ^xiii-^xx. No ijenial sacs and setce. Common setm paired, those of the inner coujile 

 closer than those of the outer couple. Spiermathecal j)ores between vii/viii and viii/ix. 

 Gizzards in v and vi. No calciferous glands. Nephridia not covered by a cfelomic man- 

 tle. Nephropores outside of seta; 4. Hearts in x, xi, xii. Sperm- sacs racemose in x, 

 xi, xii. Testes in x, xi. Color pale flesh, no pignient. Habitat, Northern Baja Cal- 

 ifornia, at Ensenada de Todos Santos. 



EXTERNAL CHARACTERS. 



Color is very pale, mottled and marbled, showing clearly the intestines and 

 blood vessels. AVhen collected this worm resembled in delicacy of color and trans- 

 parency DeUania elegans and I supposed it to be this species. Spermathecal pores are 

 separate in front of setiie 1 and 2 between vii/viii and viii/ix. Setce are ventral and 

 lateral, 8 in each somite approached in couples. The sette of the inner couple is 

 closer than those of the outer couple. The distance between the couples is about twice 

 as large as the distance between set* 1 and 2, and one and one-half as wide as the dis- 

 tance between setse 3 and 4. No penial setiie in special sacs. All setie are sigmoid 

 without sculpture. The anterior five somites are two-ringed, that is with a single 

 groove in the equatorial region, while all the following somites are four-ringed, or 



