STATE GEOLOGIST. 149 



above in the larger lakes. It appears to be but a modified condi- 

 tion of the above species, from which it differs iu its slender form 

 and especially in the very slender caudal stylets. The outer caudal 

 seta is reduced to a short ciliate thorn. The fourth foot is also 

 modified by the great enlargement of the spines and the reduction 

 of the sette. The number of the setae is the same, but they are 

 •differently disposed. The form of the operculum vulvae is also 

 slightly different. 



(?) Sp. 11. Cyclops uniangulatus, Cragin. 



Cyclo}is uniani/ulatm, Cragin. A Contribution to the History of Fresh-water Cope- 

 pocia, p. 6. 



Cragin was not conversant with the description of C. parcus, witli 

 Avhich his description agrees save in one point. It differs from C. 

 parcus in having three inner setae on the terminal joint of the outer 

 ramus of the first foot. It would be officious to suggest a possible 

 oversight here, but C. parcus has only two in type specimens 

 ((though iu all this group the corresponding ramus of the second 

 Joot has three setae), so that at present the two must be kept dis- 

 tinct. 



Sp. 12. Cyclops sciitifer, Sars. 



Not having identified this and the following species it will be 

 best to quote the descriptions. 



C. strenuo affinis. Cephalothorax sat elongatus, segmentis ultimis duobus in femina 

 ad latere valde promineutibus iiique processes exeuntibus laminares et hyalinos utrin- 

 •que inter se contiguos, quare thoracis pars posterior tamquam clypeo fornicato quad- 

 rangular! obtecta esse videtur. Segmentum l-mum abdomiuale ad basin valde dilata- 

 tum latitudine quam ad marginem posteriorem duplo niajore. Rami caudaies segnien- 

 tesantecedentlbusduobus juuctis parum longiores. introrsum clliati, setis apicalibus 

 brevisshnis, intermediarum interiore ceteris multo longiore. Antennse 1-nii paris 17- 

 articulatse, reflex^e segmentum 2-dum corporis superautes setis plurumque longis obsi- 

 ta?. Pedum structura eidem in C. strenuo similis. Articulus scilicet ultimus rami exter- 

 ioris pedum natatoriorum setis 5 instructus in paribus anterioribus duobus 3, insequen- 

 tibus duobus 2 modo aculeis marginis exterioriis armatus ; aculeorum apicalium 

 rami interiores pedum 4-ti paris exterior brevis et rudimentaris. Pedum 5-ti paris arti- 

 culus ultimus sat magnus artlculo basali parum minor extrorsum sparsim pilosus in- 

 trorsum aculeo armatus ciliato setaque longa terminali. Sacci oviferi parvi globosl 

 abdomen magna ex parte obtegentes. Longit. circit. 1}4 mm. 



Sp. 13. Cyclops al>yssoruin, Sars. 



C. strenuo et scutifero sat affluis. Cephalothorax ovatus antice obtuse truneatus. seg- 

 mentis parum ad latera extantibus. Rami caudaies longi et tenues satisque divergen- 

 4es, longitudinem segmentornm antecedentium 3 superantes, setis apicalibus longioribus 

 intermediarum interiore duplam longitudinem furcre superante, exteriore quam ilia 

 .parum breviore. Antennae i-mi paris l7-articulatse longaj et fere rectte distincte posticl 



