STATE GEOLOGIST. 143 



Sp. 1. Limnocalauiis iiiacruriis, Sais. 



A species similar to L. macrurus has been fouud in lake Michigan, 

 and probably occurs also in this state in lake Superior. We can 

 do no better than quote Sars' description. 



"Corpus gracile et angustatiim. Cephalothorax supra vlsus elongate ovatus, latitu- 

 dine maxima in medio sita antiee et postice jeiiualiter atteauatus. Caput annulum 

 unicum priebens, a latere visum parte antica altiore et coavexa slnu distincto a poster- 

 iore disjuncta, margine antico oblique descendente. Segmentum ultimum thoracis par- 

 vum neque ad latera extans in femina et mare simile. Abdomen sub-cylindricum tbor- 

 ace longius. Kami caudales valde elougati et angustati tertium longitudinis abdominis 

 partem superantes, supra et ad latera spiuulis vel pUis brevibus obsiti, intus ciliati, 

 setis 5 majoribus uniarticulatis et ciliatis, quarum 2-da ab interiore uumerata omnium 

 longissima ceterfeque extus graduatim longitundine decrescentes, exteriore ceteris 

 minore absque apice sat nmota ; seta adest prreterea alia intus adfixa ut in geueribus 

 antecedentibus tenuissiraa et simplex. Frons a latere visa obtuse acuminata appeudio- 

 ibus tentaculiformibus duabus perbrevibusinstructa. Antennae 1-mi paris reflexoe seg- 

 mentum penultimum abdominis minime attingentes, articulo ultimo setis 5, quarum 

 posteriores 2 longissimce, instructo, articulis anteceoentibus 3 setae simili postice ver- 

 gente prasditis ; dextra maris articulatione inter articulum 18-mum et 19-mum geniculans. 

 Anteunarum 2-di paris ramus exterior interiore et longior et latior, 7-articulatus, arti- 

 culo 2-do omnium maximo, sequentibus i minimis junctis articulo ultimo brevioribus 

 setisque longissimis instructis. Mandibulje ad extremitatem inferiorem in dentes ex- 

 euntes 9, quorum exteriores 2 ceteris majores, interiores 2 tenues et setiferes sunt ; pal- 

 pus longus et angustatus 3-articulatus, articulis ultimis 2 brevissimis, ramo exteriore, 

 vel aupendice brancliiale, parvo. Maxillte l-mi paris eadem fere structura ac in Diap- 

 tomo. Maxilloe 2-di paris validissimas 8-articulatje, articulis ultimis 5 in ungues exeun- 

 tibus longissimos et fortlssimos margine altero sparsim pilosos, ad apicem falcatum 

 vero nudos vel aculeispersubtile et dense obsitos ; 3-tii paris [Maxillipedes] valde elon- 

 gatte et angustatae antiee vergentes articulis 7 setis pleurumque longis prcedltis compo- 

 sita?. Pedes omues biramosi natatorii, ultimo pari in mare bi-articuiatus in pede dex- 

 tro et sinistro dissimilis, articulo ultimo in illo brevi etrobusto ad apicem quasi trun- 

 cato dentibusque 3 parvis et obtusis armato intus vero in aculeum magnum et validum 

 excurrente. in hoc valde elongate extus et ad apicem aculeato intus vero nudo. Genius 

 unicus propius raarginem inferiorem capitis situs. Animal quamquam pelluciuissimus 

 et fere omnino hyalinum, facile tamen accumulatione in thorace sat magna liquoris 

 oleosi Is-re fu'.vo-rubide colorati se prodit. Longit. circit. 2Vk mm." 



FAMILY CYCLOPID^. 



Contains five genera, viz: ThorelUa, C^jclops, Oithona, Lopho- 

 pJwnts and Cijclojnna; passing, by the genera Misophria and Pseit- 

 dO'Cijclops, into the Calanidai or marine copepods. The affinities of 

 these little known genera need further study, as they are very in- 

 teresting, the question being still open in how far the cyclopoid 

 forms are altered by adaptation to saline habitat, if such an adapta- 

 tion takes place at all. 



Cephalothorax ovate and usually much more robust than the 

 abdomen; anterior antennae seldom longer than the cephalothorax, 

 those of the male alike on both sides and modified for the purpose 

 of clasping; posterior antennas unbranched (i. e. palpus wanting); 



