280 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



1887. Rhopalonaria (part) Vine, Proc. Yorkshire Geol. & Polyt. Soc, 

 IX, p. iSs, pi. 12, fig. II (? 12). 



Fossil zoaria of which only the creeping base is known. This 

 attaches itself to foreign bodies and consists of strings of sausage- 

 like, bulbous fusiform or pear-shaped internodes or vesicles varying 

 greatly in size in different species. Surface of internodes minutely 

 punctate, while a number in each colony exhibit a larger pore-like 

 depression, usually near one end of the vesicle or internode that is 

 regarded as marking the point where erect zooecia were attached. 



Genotype. — Alloncma hotelloides new species. 



The distinctive features of this genus, when compared with Hetero- 

 nema, Vinella, and Rhopalonaria, are ( i ) the separation of the creep- 

 ing base into distinct vesicles or connected internodes, and (2) the 

 minutely punctate surface of same. The second character has been 

 observed in all the species now referred to the genus except A. ? uiin- 

 iinuni. In distinguishing the various species we have been obliged 

 to rely chiefly on differences in the size of the internodes. How- 

 ever, a certain average seems constant for each species, so that we 

 have experienced little difficulty in classifying our collections. 



A. fusiforme (Nicholson and Etheridge, Jr.) and our A. siibfiisi- 

 forme and A. ivaldroncnse, are closely related but depart in size of 

 form and internodes obviously from the more typical Silurian and 

 Devonian species of the genus. The latter compare in the form of 

 their internodes with Valkeria, the former remind more of the basal 

 vesicles of Aitea. As the zooecial characters of these two recent 

 genera are different enough to cause them to be widely separated in 

 the classification of the Bryozoa, it is possible that these fossil bases 

 likewise belong to zoaria with very distinct zooecia. However, it 

 will perhaps forever be impossible to determine this point, and our 

 only reason for referring to the possibility is the wish to avert 

 off-hand unfavorable criticism of our " species." These may in some 

 cases appear to be drawn too fine, but we think not, and for two rea- 

 sons : In the first place, all we have of these Bryozoa are the creeping 

 bases to which the erect and solitary zooecia were attached. In clas- 

 sifying recent Ctenostomata, very little dependence is placed on the 

 bases, the family, generic, and even specific characters being derived 

 almost entirely from those of the zooecia. Our second reason is the 

 unlikelihood of one and the same species passing from one geological 

 system to the next, as, for instance, from the Silurian to Middle or 

 Upper Devonian. 



Concerning the systematic position of the new genus, it seemed 

 at first that the punctate surface of the internodes, and their frequent 

 isolation in some of the species, should be regarded as the determining 



