M GEAF ZU SOLMS-LATJBACH— MONOGRAPH OE THE ACETABULARIE^. 



of mud, small sea-stars, and remains of algge forming the dried specimen. Schenck's 

 specimens from Cabo Erio in Brazil are, on the other hand, well preserved, and are found 

 on mussel- and snail-shells. If Mobius did not observe the spicula? and took the plant 

 merely for an Acetahularia, it was probably because he examined it only after 

 decalcification. 



b. Forms known only in a fossil state. 



Of these only the lime-spiculse with the spores Averc known for a long time. These, 

 however, are sometimes several together, when also the remains of the partition-walls of 

 the cliambers are preserved. But quite recently a form belonging here or to Chalmasia 

 with complete caps and fragments was found by Andrussow and described by him as 

 Acetahularia miocenica. In placing it in the genus Acicularia it cannot retain this 

 specific name, since an Acicularia miocenica, Reuss, exists already. It may therefore be 

 called Acicularia Andrussoivi. The spores have vanished in all cases from the spiculse of 

 the fossil Acictilarics, and cavities usually opening outwards mark their places. These 

 holes are either equally distributed all round the spiculae or they are present only on the 

 upper and under surfaces. The species of the former kind are equivalent to d'Arcliiac's 

 genus Ac icidaria, those of the latter to the genus Briardina^ Mun.-Chalm., as kindly com- 

 municated to me in writing by Munier-Chalmas. I am doubtful whether it be expedient 

 to separate both groups generically on so slight a distinction. Prom the fragments I have 

 seen and Carpenter's figures I perceive that Acicularia contains a large number of fossil 

 species, and among them some of those treated of by Carpenter fall imder the type 

 B?nardina (compare his plate 29. fig. 11). I must refrain from a description of these, 

 owing to the scarcity of material at my command. It is to be hoped that Munier- 

 Chalmas himself will deal with them at no distant date. Only those species can be 

 mentioned here that have obtained a place in the literature of the subject, and it must 

 be expressly stated that their position in the genus Aciculai^ia, as understood here, 

 is by no means certainly determined. The mere spiculse of Halicoryne of the type of 

 K. spicata would be, w^ere they fossil, indistinguishable from those of a true Acicularia, 

 though they come from a plant of wholly difl'erent structure, and from the constitution 

 of both the species of Halicoryne it appears not to be impossible that at an earlier period 

 there may have existed also ChalmasicB with clustered spores, which in that case would 

 come under the parent genus Acicularia. 



2. Acicularia Andrussowi, Solms. 



Fertile discs circular, flattened, with up to 90 peripheral, very narrow ray-chambers 

 with obtuse ends. The partition-walls dividing the chambers extraordinarily thick, 

 sometimes as broad as the chambers themselves, sometimes a little less. Spore- cavities 

 in two rows on both the upper and under sides of the spicula, filling the chambers. Corona 

 superior and inferior, according to Andrussow, in the form of flat bands. (Plate III. fig. 13.) 

 Acetahularia miocenica, Andr. In the Miocene (2nd Mediterranean bed) of the Crimea, 

 singly in the Tschokkrak lime of the peninsula of Kertch, rock-forming in white lime with 



