174 l^rof. Mohl on the Import of the » 



length and one-eighth in thickness ; these soon become attenuated, 

 either by the agitation of the water or the coming into contact 

 with something, and are drawn into very long threads of great 

 tenacity ; they stick to everything they touch, and from these the 

 animals are called " cotton spinners " by the fishermen. This 

 small bunch is drawn into a large mass of threads, so small that 

 the finest sewing-cotton is not equal to it, and is no doubt one of 

 the means of defence provided for its preservation ; for I have 

 seen a crab so completely entangled in it as not to be able to 

 move, and a fish only able to get away after a long struggle. If 

 much irritated they throw out the whole of their intestines ; this 

 is invariably the case after being kept in confinement two or 

 three days ; and even after they have done so they have lived 

 three days, and their tentacula performed all their offices as if the 

 animal was strong and healthy. They soon decay when dead if 

 left out of the water, and from their peculiar construction it is a 

 difficult matter to preserve or dissect them. To the physiologist 

 they offer a rich treat. I know nothing of this science ; I regret 

 it : my object has been to watch their actions and habits, and I 

 fear I have too long occupied your time. I would here just 

 mention that this Holothuria differs from the P solus Forbesii of 

 Mr. Couch, noticed in the second part of his ' Cornish Fauna,^ in 

 having twenty tentacula instead of eighteen, and the suckers are in 

 rows, which was not the case in his. I therefore claim it as new to 

 the British fauna, which latter circumstance Professor Forbes con- 

 firmed at the late meeting of the British Association at York. 



The annexed engraving, Plate XIV., represents the " Nigger '* 

 of the natural size ; fig. 3, the head with the mouth downwards, 

 showing the tentacula spread out. 



XXV. — On the Import of the inferior Palece of the Grasses. 

 By Hugo von Mohl*. 



[With a Plate.] 



There are few points in vegetable morphology respecting which 

 so great a difference of views prevails as that relating to the 

 origin of the floral envelopes of the Grasses. To remove this dif- 

 ference of opinion, at least with respect to one of the points in 

 question, it is above all requisite to ascertain with certainty 

 whether the inferior palea takes its origin from the same axis as 

 the superior palea (or, according to Robert Brown's view, the two 

 leaves composing the upper palea), or whether the two result 

 from different axes. In the first case we undoubtedly accede to 



• From the Botanische Zeitnng for Jan. 17, 1845. Translated and com- 

 municated by W. Francis, Ph. D., F.L.S. 



