240 REPORT ON THE STATE CABINET. 



having been applied to a genus of insects, the name Diplograptus * of 

 McCoy has generally been adopted. 



The distinction indicated would at one time have expressed a character 

 perfectly trenchant ; but the discovery of such forms as G. ramosus t and 

 G. furcatiis shows the occurrence of both a single and a double series of 

 cellules upon the same stipe, or, more properly, shows the basal portion 

 consisting of a simple stipe, with two parallel ranges of cellules; which 

 dividing at some distance above its origin is continued as two simple 

 stipes, each with a single range of cellules. These cellules are on the 

 outer margins, and are a continuation, without interruption from those of 

 the lower part of the stipe. Including these, therefore, in the same group 

 with G. pristis, the subdivisions indicated would have less value for the 

 purposes of study ; but I believe these latter forms may be separated on 

 other grounds, as will be shown farther on; so that with our present 

 knowledge we may still recognize Diprion, = Diplograptus, as a well- 

 marked and clearly-defined sub-generic group of Graptolithus proper, 

 having such forms as G. pristis among the typical species. 



M. Geinitz has more recently proposed the name Monograptus to 

 include Monoprion and Rastrites of Barrande ; placing under this 

 genus, as his typical species, G. sigittarius of Hisinger, which has usually 

 been regarded as the typical form of Graptolithus of LiNNiEUS. 



The genus Cladograptus ;[ is also proposed by M. Geinitz, to include 

 the species G. ramosiis and G. furcatus (Hall), G. nmrcMsoni (Beck), 

 G. serra (Brongniart) , G. forcliliammeri (Geinitz), G. sextans and G. serra- 

 tulus (Hall). At the same time the British palaeontologists, adopting 

 the name Didymograptus (McCoy), place under that genus G. murchi- 

 soni (Beck), G. caduceus (Salter), G. sextans (Hall), G. geminus, (Hisin- 

 ger), G. Mrundo (Salter), and other similar forms. Those which are 

 made the typical forms of the genus by Geinitz are the " species geimllce " 

 of Bronn, Avho included under that term the G. geminus (Hisinger), and 

 G. miirchisoni (Beck) , which are by no means nearly related to G. ramosus 

 or G. furcatus. The first named two species, which were the earliest 



* In the genera proposed by myself, I have chosen the termination graptus instead ofgrapsus, 

 since the latter is in use in the nomenclatui'e of Crustacea. 



■ t The subdivision of this species beyond the first bifurcation, represented in the Paleontology 

 of New York, Vol. i, pi. Ixxiii, fig. 3, is erroneous; the specimen consists of two individuals, the 

 base of one being placed directly in the axil of the other. 



J Cladograpsus (Geinitz). Syn. Graptolithus auctorvm; species gemellte, Bronn {Die Vcrstieiier- 

 ungen der Grauwacken formation in Sachsen, etc., Heft i, Graptolithen, p. 29). Monograpsus, 

 id. ibid. p. 42. Sjn. 3Ionoprion et Bastrites (Barrauve); Graptolithus, Svess. i>iot Clado- 

 graptus, Carbdtheiis. See supplementary note. 



