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REPORT ON ZOOLOGY, MDCCCXLIV.

and in most zoological treatises scarcely anything has here-tofore been said about them. On which account also theReporter is induced to give in this place the families andgenera instituted by Oersted, together with his diagnoses.

In the first place, he considers the Nemertini as a sub-orderof Yermes apodes, which sub-order is designated by him asCestoidina, and is characterised as follows: Corpus lineareteretiusculum rarins depressum, multo longius, quam latius,indistincte annulatum, mucosum, ciliis vibrantibus obsitum ;musculi distincti, non vero nervi (?). Oculi 2, 4, 6, 8, 10,multi, vel nulli. Organa respiratoria specialia nulla, velfissune respiratorise laterales in capite aquse ad cordum parietesaditum conciliantes. Circulatio completa et corda duo. Tubuscibarius simplex cum oris apertura infera (rarius terminali)et ano terminali. Os nullum exsertile. Sexus duo, inutroque organum copulationis stimulandse. Testiculi etovaria cava ne minimum quidem forma inter se discrepantiatantum modo contento (ovulis aut spermatozois), compluraiii utroque latere uniuscujusque segmenti. These Cestoidinaare divided by Oersted into two families, with eight generas.These are:

Fam. I. — Nemertina. Os inferum, anus terminalis.

(1.) Corpus filiforme, utrinque aequaliter attenuatum(caput nullum distinctum), fissurse respiratorise nullse.

Os et ovaria aut testiculi ab apice valde remota.

1 Gen. Cephalothrix Oerst. with two species.

Os et ovaria aut testiculi ab apice non multo remota.

2 Gen. Astemma Oerst. with two species.

(2.) Corpus lineare teretiusculum, antice plus minusvedilatatum (caput distinctum), fissurse respiratorise distinctseaut nullse.

a. Caput a corpore eonstrictum, fissurse respiratorisenullse.

3 Gen. Borlasia (Oken) Oerst. with eight species.

b. Caput a corpore non eonstrictum, fissurse respiratoriseplus minusve distinctse.

a. Oculi numerosi acervati.