264 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 



Cliydoriis letourneuxi Eichard. 



Eichard '88. 



Testa a latera visa subrotundaia, sulcis curvatis (10-12) e medio exeuntibus, ad 

 margines anticos liberos porrectis, antice manifestis ut in Plturoxus adunco, ornato; 

 testis cetera laevis, marginesuperiore prominente, postice leviter sinuato, margioalibus 

 posterioribus et inferioribus rotundatis. Valoulorum margines inferiores postice 

 ciliis longis instructi, margines superiores dentati. Rostrum breve et obtusum. 

 Antennae 1 mi paris ad basin crass aj, rostro breviores, setis gequalibus. Antennae 2 

 di paris setis 7 prseditse. Macula nigra oculo duplo minor, inter oculum et apicem 

 rostri fere in medio sita. Postabdomen apicem versus rotundatum, unguibus termi- 

 nalibus brevibus isevibus ac robustis, aculeis ad basin 2, quorum interior alteio 

 multo brevior, armatis; margo superior in medio sinuatus supra medium processum 

 obtusum format et infra buuc aculeis minutis dense obsitus. Spinulis mintutibsi- 

 mis sparsim in lateribus post-abdomen instructnm. Color corneus. Longit. circit 

 0.5 mm. Mas ignotus. Algeria and Tunis. 



Ghydorus alexandroivU and C. tuberculatus of Poggenpol are confess- 

 edly imperfectly described. We incline to the belief that there are 

 not more than four good species in this genus, but extended study of 

 the conditions of variation are necessary. 



GENUS ANCHISTROPUS Sars. (?) 



Very similar in form to Ghydorus; valves gaping below anteriorly; 

 antennules small; process of labrum rounded. Post-abdomen atten- 

 uated toward the end, densely covered with fine teeth; terminal claws 

 denticulate. First foot with a powerful claw, protruding beyond the 

 shell. Eye very large. Shell indistinctly reticulate. Sars says of 

 his AnehiHiroims emarginatus that on cursory inspection it would be 

 taken for the young of Ghydorus glohosus. He found but few speci- 

 mens, about 0.35 mm. long. The suggestion is still possible that the 

 young males of some Ghydorus are here mistaken for a new genus. 

 The males of Ghydorus glohosus were not known till 1878, and their 

 early form is still unknown. The young females have a tolerably 

 strong claw, though it is not much curved. I once found a 

 peculiar Lynceid measuring 0.46 mm,, with unevenly but distinctly 

 reticulate shell, slender abdomen, and a strong claw which was 

 dentate. There were several young (more than two), and the shell in 

 these was more regularly reticulate. All efforts to find a second 

 specimen failed, and the one seen was somewhat mutilated; hence I 

 am unable to determine its real position. 



GENUS MONOSPILUS Sars. 



Head separated by a depression from the body; shell high, com- 

 pressed, posterior margin somewhat less than the greatest height of 

 the shell. Post-abdomen broad, ornamented with lateral and posterior 



