Reviews — Carl Wmnan — On the Biplograptidce, etc. 431 



He believes that the polypary of Climacogrnptus scalaris is built 

 np in the following way : The conical sicula is on the side of the 

 second thecal series, and the apex coincides with the axis of the 

 polypary. It sends out the connecting canal on the side facing the 

 primordial series, and this runs along the lower portion of the sicula 

 and opens into the proximal part of the biserial chamber. This 

 chamber he defines as that part of the common canal below the 

 median septum ; it gives rise to two thecse on each side, the rest of 

 the cavity of the rhabdosoma being divided by a median septum into 

 two uniserial canals originating in a common chamber. 



CUmacograptus iitternexus is similarly developed, but is charac- 

 terized by tlie free prolongation of the lower lamina of each thecal 

 partition, which extends downwards over the apertui'e in a manner 

 resembling 3£. priodon (Bronn). The median septum is undulated. 



Diplograptns palmeus. — 'J'he septum is incomplete, and tliecal series 

 therefore originate from one biserial canal. 



D. bellulus. — This species is characterized by the long proximal 

 prolongation of the virgula. There is no trace of a median septum, 

 and the common canal is very narrow. 



Cephahgraphis cometa. — The connecting canal is almost at the 

 base of the sicula, and is directed somewhat outwards. It opens into 

 the common biserial canal, which does not send out the first theca of 

 the second, series until far beyond the pointed end of the sicula. 

 The median septum is incomplete. 



The author concludes with the observation that the central cavity 

 of the rhabdosoma may consist of two uniserial canals, separated by 

 a more or less complete median septum, and originating from a short 

 biserial chamber, or a single biserial canal. 



G. L. E. and E. M. E. W. 



IV. — "UeberDiplograptid^," Lapw., and "Ueber Mon^oguaptus," 

 Geinitz. By Carl Wisman. Bull. Geol. Instit. of the Univ. 

 of Upsala. Vol I, No. 2. 1893. 

 rnHE author has been able to make very complete researches on 

 JL the structure of the proximal part of the polypary in the 

 Diplograptidse and in Monograptus, owing to the method of pre- 

 servation of his specimens. The polypary was embedded in lime- 

 stone, and was isolated and stained by means of acid and Schulze's 

 macerating fluid. 



As regards the Diplograptidee, Wisman lays stress on the follow- 

 ing points: The sicula consists of two parts, the proximal and distal, 

 differing in their form and external sculpture. This gives rise, on 

 the right-hand side, to only one bud, so that the Diplograptidse are 

 Monoprionidian. This bud gives rise to a theca, and each subse- 

 quent theca develops from the one next below it, but on the 

 opposite side and not from a common canal. The polypary, together 

 with the virgula, develop at first both proximally and distally, but 

 at a later period the distal growth alone persists. The sicula does 

 not lie embedded between two branches grown together along their 

 dorsal surfaces, as was formerly supposed, to be the case, but is at 



