THAXTER. NEW LABOULBENIACEAE. 17 



externally and inferiorly to form a free buttress-like margin, much as in 

 H. Paranensis, which almost wholly covers the single fertile cell. Peri- 

 thecium yellowish, straight, nearly erect, the base bulging very slightly ; 

 but hardly broader than the ascigerous part, which is relatively large, 

 long, subcylindrical, or slightly inflated ; the distal part, relatively short, 

 rather abruptly distinguished ; the posterior cell row, which is external 

 in relation to the host, more prominent, with larger thick-walled cells, 

 the fifth from below prolonged to form a long, bluntly tipped, erect, 

 horn-like, subterminal projection, distally curved inward above the short 

 slightly incurved pointed subcorneal tip. Total length of perithecium 

 (exclusive of base) to tip of process 150 /u ; to tip 115 p: ascigerous part 

 70-75 X 28-30 n, distal part to tip 35-40 /x ; the process, free part, 

 25-30 n, whole cell 40-44 fi. Secondary receptacles both together 

 55-65 X 25 fx. Total length to tip of process 175-185 p. 



On Diploptera dityscoides Serv., Ascension Island, South Atlantic ; 

 Mus. Comp. Zool., No. 1371. 



Herpomyces tricuspidatus nov. sp. 



Male individual variably developed, the terminal cell rounded apiculate, 

 but as a rule soon indistinguishable through proliferation, the simpler 

 forms very similar to well-developed individuals of H. Perijilanetae, the 

 more complicated and most frequent type similar to the fertile branches 

 of the male individual in H. Ectobiae, producing, through continued 

 successive proliferation, a dense compact more or less appressed tuft of 

 antheridia which appear to be associated with undifferentiated sterile 

 branchlets. Antheridium long flask-shaped, hardly distinguished from 

 the usually several celled branchlet which it terminates. Total length 

 to tips of antheridia 75 p. 



Female individual. Primary receptacle small, surmounted by two 

 rounded cells constricted at the septa, the distal one bearing a small 

 sharp spine subtended by the usual minute blackish projection : the 

 subbasal cell producing apparently a single fertile branch which divides 

 at once, growing in opposite directions to form the somewhat irregular, 

 and variably developed, secondary receptacles, which may creep exten- 

 sively ; the component cells, which are often very numerous, being verti- 

 cally elongated and becoming arranged in two more or less complete 

 rows ; the inner mostly fertile, producing perithecia of which there rna} r 

 be twelve or rarely more ; the outer becoming several times closely 

 divided vertically, the cell-group which thus gives rise to the perithecial 

 stalk, laterally connected with corresponding adjacent cell-groups through- 

 vol. xxxvm. — 2 



